Recording instrument.



BEST AVAILABLE COP- W. H. PRATT. RECORDING INSTRUMENT. APPLICATION FILED APR.7.1903.

919,459. Patented Apr. 27, 1909.

2 SHEETS-SHEET 1.

Witnesses.

f. v Inventor William H. Pratt.

BEST AVAILABLE 00 W; H. PRATT.

- RECORDING INSTRUMENT.

1 APPLICATION FILED APB.7.1903.

v 91 9,459; Patented Apr. 27, 1909.

2 SHEETS-SHEET 2.

Witnesses I I t g I WiHZIT E EL Ia'L'L.

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- rue NORRIS PKYERS ca. \usnm roN. n. c.

To all whore it concern:

g No. 919,459.

sssrAy/umsis UNITED STATES Parent FFTQE.

WILLIAM H. PRATT, OF LYNY MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY,

A CORPORATION OF NEW YORK.

RE CORDING INSTRUMENT.

Application fiiea April 7,

- Be it known that"T,':l/VILLIA1\[ H. PRATT,

citizen :of the 'United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Recording Instruments, of which the following is a specification.

1 .My invention; relates particularly to the construction of instruments in which .an element moving inres onse to the changes in value of some variable quantity causes a record to be made upon a surface having a I progressive movement, the speedwith which the surface 'movesbeing usually some func tion of the time. 1

- The object of myinvention to'. improve the construction 10f.- instruments of this character and my. invention consists in certain novel features. of arrangement, constructionmand combination which will be definitelypointed out in the claims annexed to and forming part .of this specification.

wFor asbetter understanding of my invention reference may be had to the accompanying drawings in which I have illustrated one embodimentiof my invention.

Figure 1 is an'end elevation of the instrument partly broken'away and partly in section with the'axis of the instrument horizontal insteadof vertic'alas it is in operation; Fig. 2 is'a detail view. of the marking element; Fig. 3 is a front view in elevation of the instrument shown in Fig. 1 with part of the recording drum broken away. Fig. 4 is an enlarged view taken similarly to Fig. 3 showing certaindetails; Fig. 5 is view taken atri ht angles to Fig. 4; and Fig. 6 is a partia sectional elevation taken on the line 66 of Fig. 3.

The instrument as a whole is supported upon a vertical base 1 and is surrounded by a suitablecasingwhich may be of glass. A frame or bracket 2.extending from the base carries that portion of the instrument that is des' 'ned to measure the variations of the variab e quantity. In the particular embodiment of my invention which 1 have illustrated in the drawings, the instrument is designed to record the voltage existing between points in an electric circuit. 'The measuring mechanism consists of a pair of fixed coils 3 and 4 and a air of movable coils 5 and 6 angularly dispi aced with reference to the first-mentioned coils. The fixed Specification of Letters Patent.

1 coils are secured to a cross-bar 7 of the frame 2. The coils 3 and 4 as well as the coils 5 and 6 are substantially rectznigular. The coils 5 and 6 are larger than the coils 3 and 4 which they embrace. The movable coils are secured to a vertical tubular shaft 8. The coils 5 and 6 which are located one on each side of the shaft 8, as are the-coils 3 and 4, are separated by space blocks- 9 and 10 which may be made of brass. Clamps 11 and 12 are employed for clamping together the coils 5 and 6 and the blocks 9 and .10 respectively. The blocks 9 and 10 are apertured to receive the hollow shaft 8.

Centrally apertured plugs or blocks 13 are placed in each end of the tube 8. A fine wire 14 such'as a piano wire slightly smaller than the apertures in the plugs 13 passes lengthwise through the shaft 8 and forms a means for positioning the shaft and thereby the movable coils. The ends of this wire pass through openings in the frame 2 and are secured to plugs 17 carriedby plateslS which are held in place against the frame 2. Disks 15 and 16 carried on the innersides of the upper ends of the frame 2 and provided with centrally located apertures through which the wire passes, assist in positioning the wire. The aperture in the disk 15 passes through a central boss 15 extending from the lower face of the disk 15 for some distance.

I The weight of the movable element of the meter is sustained by a pair of threads or wires 19 which extend from the upper side of the block 9, one on each side of the shaft 8 toan apertured disk 20, thus forming a bifilar suspension. The lower end of the boss 15 is beveled and fits into the aperture in the disk 20 so that the end of the boss is immediately above the end of the hollow tube 8. The aperture in the dish 20 is large enough so that the beveled end of the boss 15 does not bear against the walls of the aperture. The disk 20 is supported from the disk 15 by a pair of diametrically opposed flexible members 21. The plane in which the flexible members 21 are located is perpendicular to the plane containing the wires or threads 19. This construction forms a very desirable means of supporting the Weight of the movable element of the meter, as the flexible members 21 with the disk 20 correctly distribute the weights carried by the two filaments 19 and form an equalizer 33 and when t which obviates the necessity of making the filaments l9 exactly the same length.

Studs 22 in line with the-shaft 8 and carried by brackets 23 secured to the outside of the frame 2 each have connected to them one end of one of a air of spiral springs 24. The other ends of these springs are secured to arms 25 which extend parallel to the shaft 8 and are in turn carried by a pair of arms 26. The arms 26 are carried by and extend perpendicularly from the shaft 8 and carry at their outer ends a pair of jewel screws 27 in which a shaft '28 parallel to the shaft 8 is pivotally mounted. jA tie-bar 29 connects the arms 26 intermediate their ends.- A helical spring 30 wound around the shaft 28 and having one end secured to the shaft and the other end 31 "elongated to bear against the tie-bar 2-9, tends to rotate the shaft 28 in one direction. A short arm 32 carried by the shaft 28 engages with a spring stop 33 carried by the tie-bar andprevents the shaft 28 from being rotated against the action of the s ring morethan a predetermined amount. hespring stop 33 isprovided with a bend e shaft 28 is rotated to bring the end'ofthe'arm 32 past-this bend,the

- resiliency of the spring 33 is sufficient to hold the arm 32 and shaft 28 in the position which -it has assumed" against the action of the spring 30.

An arm 34 extending perpendicularly from the shaft 28 near its middle portion carries at its "outer end a suitable marking device." This marking device may be an ink receptacle',pencil or the like. Vveights 26 are carried by arms extending perpendicularly from the opposite side of the shaft 8 from which the arms 26 extend. I These weights counterbalance the weight of the arms 26 and mechanism carried thereby.

The record surface, with which the marking device 35 is held in engagement by the spring 30, consists of a strip of paper wound upon a drum 36. The drum 36 is carried by a revolving shaft 37 placed perpendicularly to the shaft 8 and supported in any suitable manner from the base 1. A suitable mechanism 38, which may be a spring motor, rotates the drum at a uniform speed in the direction of the arrow shown in Fig. 3. The drum 36 consists of a rim 36 which may be formed of sheet metal, and a pair of disks or spider portions 43 and 43. The ends of the rim portion 36 are turned up to form outwardly extending flanges which assist in positioning the record strip. The outer edges of the disks or spiders may be turned over as clearly shown in Fig. 3 to form cylindrical portions which abut against the inner side of the rim portion. The disks and drum portion may be secured together in any desirable manner. The spider 43 is near the right-hand side of the drum as viewed in Fig. 3 and the spider 43 is placed about midway of seams/gamers the drum. The spiders 43 and 43 turn loosely upon the shaft 39. The shaft 39 to the left of the spider 43 as viewed in Fig. 3 is enlarged to form a shoulder against which the disk 43 abuts. The shoulder and the disk thus cooperate to prevent a longitudinal movement of the drum along the shaft toward the left as viewed in Fig. 3. The shaft 39 which is in alinement with and may be an extension of the driving shaft of the spring motor has its outer end journaled in a bearing carried by the crossbar '7 of the frame 2. It has not been thought necessary to illustrate the construction of this hearing. The shaft 39 extends perpendicularly to the shaft 8 but is located somewhat nearer to the base 1. The construction of the drum is such that the coils can extend into the drum for. a considerable distance as clearly shownzin Fig. 3. The periphery of the drum thus overhangs the coils. This nesting of the coils'within the drum adds largely to the compactness of the instrument and is a desirable feature. Suitable clips 36 are carried atthe periphery of the drum by means of which the record strip may be secured in position.

' A collar 40 secured to the shaft 39 has extending from it perpendicularly to the shaft, a plurality of flexible arms 41. are turned over at their outer ends and are secured to a disk 42 as is clearly shown in Fig. 3. The disk 42 is formed with a central aperture through which the shaft 39 passes. The resiliency of the arms 41. causes the disk 42 to be pressed so firmly against a disk-43 forming part of the drum 36 that a rotation of the shaft 39 will normally cause a rotation of the drum 36 but not so firmly but that the drum may be set at any desired initial position.

The mechanism for driving the drum may be constructed to cause the drum to make one complete revolution in every twelvehours, twenty-four hours, or other desired interval of time. In such cases it may be desirable to construct stops which will automatically engage the drum and prevent its further rotation whenever one complete revolution has been made. In Fig. 3 I have shown stops 44 and 45 carried by the drum and the base 1 respectively capable of pro ducing this result.

A stud 46 projecting from the disk 43 has secured at its outer end one end of a spiral spring 47. The other end of the spiral spring is secured to 'a fixed support 48 projecting from the framework of the spring motor 38. The spring 47 tends to prevent a rotation of the drum in the direction of the arrow shown in Fig. 3 thus opposing the action of the spring motor and acts always to take up the back lash of the gearing which drives the drum.

As I have before stated, the particular instrument illustrated is a volt-meter, the

- meter shaft mounted to oscillate and means second shaft, and a spiral spring coiled about BEST AVAILABLE COP.

coils 3, 4t, 5 and 6 being all arranged in series. Binding posts 49 and 50 carried by the base 1 5 form the terminals of the meter. Flexible conductors 51, 52 carried by the shaft 8 are in electrical contact with supplemental binding posts or terminals 53 and 54 mounted on the cross bar 7 of the frameQ. I have not thought it necessary to illustrate the exact details of the arrangement of the conductors connecting the coils since these arrangements form no part of my present invention. V

While I have described the instrument as arranged to operate as-a volt-meter, it will i be entirely obvious to one skilled in the art 1 that the particular instrument which I have described might be constructed to operate either as an ammeter, Wattmeter, or the like. It will also be apparent that many of the features of novelty disclosed in this case are g not limited to their use in connection with electrical measuring instruments but are useful in other relations.

What I claim as new and desire to secure by Letters Patent of the United States, is,

l. A recording instrument comprising a meter element mounted to oscillate, a pair of arms carried by said element, a shaft journaled in said arms, and a spring surrounding said shaft and arranged to rotate said shaft relatively to said arms.

2.. A recording instrument comprising a meter shaft mounted to oscillate, means for supporting a record sheet adjacent said sha arms mounted on said shaft, a second shaft pivptally mounted in said arms parallel to the meter shaft, a marker mounted on said said second shaft and arranged to normally hold said marker in engagement with the record sheet.

3. A recording instrument comprising a for supporting a record sheet, an arm mount- 5 tion with 5 ed on said shaft to extend perpendicularly therefrom, a spiral spring having its axis in ahnement with the shaft with one end fixed and the other end secured to said arm at a distance from said shaft, and a marker pivoted to said arm to engage said record sheet.

4. In a recording instrument the combinaa rotatable member, a driving mechanism for rotating said member, a

r friction clutch between said mechanism and i said member arranged to drive said member,

and a spring connected to said rotatable member to oppose the action of said driving mechanism.

5. lira recording instrument, the combination with a rotatable drum for carrying a record sheet and a driving mechanism for rotating said drum, of an electric meter com prising relatively movable coils nested in said drum, and a marker moved over the record sheet on said drum by said meter.

6. In a recording instrument, the combination with a meter shaft, coils mounted thereon, and a marker carried by said shaft, of a rotatable record drum comprising a rim arranged to overhang said coils, and driving mechanism for rotating said drum.

7. In a recording instrument, the combination with a movable meter element and a marker carried thereby, of a rotatable drum arranged to support a record sheet in contact with said marker, said drum comprising a spider and a rim extending laterally from the spider to overhang said movable meter element, and driving mechanism for rotating said drum. I

In Witness whereof, I have hereunto set my hand this fourth day of April, 1903.

W'ILLIAM H. PRATTI.

Witnesses DUGALD Mali. lcKuLor, JOHN A. BlCh'lANUS. 

